1. Field of the Invention
Priority is claimed on Japanese Patent Application No. 2003-312743, filed Sep. 4, 2003, the content of which is incorporated herein by reference.
The present invention relates to an excellent method in terms of utilization efficiency of deuterium atoms for producing deuterated methyl methacrylate-d8 represented by the formula CD2=C(CD3)COOCD3 (D represents a deuterium atoms), which is hereinafter referred to as MMA-d8 sometimes, from acetone-d6, (CD3)2CO, and methanol-d4, hereinafter sometimes referred to as CD3OD. MMA-d8 is a long-awaited compound as a raw material for plastic optical fibers and optical waveguide materials having low transmission loss.
2. Description of the Related Art
Plastic optical fibers are essential for large capacity communication networks installed in houses and offices and are a functional medium having a combination of low losses and large bandwidth of quartz optical fibers and tractability of copper wires. A polymer optical wave guide which has a large thermooptical effect and is easy to process is a long-awaited material in constructing optical communication devices such as optical waveguides instead of conventional glass or inorganic crystal materials.
An inexpensive and processable polymethylmethacrylic acid (PMMA) heretofore has often been used as a material for polymer optical communication. PMMA is mainly used in visible wavelength regions because of high absorption loss of the optical signal due to carbon-hydrogen bonding at wavelengths in the near-infrared region which is used for the optical signal, however, transmission loss is also high at visible wavelength regions since the overtone of near-infrared absorption appears in the near-infrared region. Deuterated PMMA in which hydrogens are replaced by deuterium atoms has been developed to solve this problem. Deuterated PMMA makes it possible to form a material for optical communication having low transmission loss due to a shift to the long-wavelength side of near-infrared absorption.
MMA-d8, which is a raw material of deuterated PMMA, may be prepared by applying the acetone cyanohydrin method (ACH method), generally. In this method, methylmethacrylate-d8 is prepared by synthesizing deuterated acetone cyanohydrin from acetone-d6 and hydrocyanic acid or deuterated hydrocyanic acid, reacting with sulfuric acid or deuterated sulfuric acid, and esterifying of methanol-d4 or methanol-d3, hereinafter referred to as CD3OH, the methyl group of which is fully deuterated (see documents 1 and 2).
Acetone-d6 as a raw material is prepared by reacting acetone and deuterated water under the presence of potassium carbonate or reacting acetone and deuterated water under the presence of sulfuric acid. On the other hand, deuterated methanol and methanol-d4 are prepared by reacting deuterium and carbon monoxide in the same way methanol method is normally synthesized. CD3OH is produced by bringing methanol-d4 into contact with a large quantity of water is nor, for example, refer documents 3 and 4.
As described above, methanol-d4 is easier to synthesize and acquire as deuterated methanol than methanol-d3. When methylmethacrylate-d8 is synthesized by the conventional ACH method using methanol-d4 and acetone-d6 as a raw material, reacting acetone-d6 with normal hydrocyanic acid to produce acetone cyanohydrin-d6, further treating with normal non-deuterated sulfuric acid, and reacting with methanol-d4, 2 atoms of deuterium atom is mixed into waste sulfuric acid water and waste ammonium sulfate. A great amount of work is needed for recovering these deuterated atoms from these waste, expensive deuterated atoms would be loss in large quantity when waste, and a large amount of energy loss occurs when recover, thereby production costs increase.    Document 1: J. Poly. Sci., vol. 62, S95 (1962)    Document 2: J. Phy. Org. Chem. vol. 8, P249 (1995)    Document 3: Bull. Soc. Chim. Belg., 56 (1947) 81    Document 4: J. chem. Phys., 10 (1942) 694